This invention relates to the art of manufacture of field emission displays. In one specific application, the present invention relates to the fabrication of patterned phosphor screens for high resolution displays.
In the manufacture of field emission displays, photoresist masks are used, as described in, for example, U.S. Pat. No. 4,891,110, issued to Libman, et al., on Jan. 2, 1990, and listing Zenith Electronics Corporation as the assignee, which patent is incorporated herein by reference.
As described in Libman, the photoresist is fixed in certain areas over a conductive surface, the unfixed photoresist is then removed by a wash, such as water, and the exposed conductive surface is then subjected to a cataphoretic bath to apply a phosphor to the conductive surface. After that application, the fixed photoresist material must be removed, which is accomplished in the field emission display art by way of washing with, for example, a hydrogen peroxide solution Such washing causes mechanical agitation and dislodges particles of phosphor, resulting in unacceptable displays. This quality problem becomes even more critical as phosphor spot size or line width shrinks to achieve higher resolution products.
Accordingly, there is a need for a method and system for manufacture of field emission displays that will not mechanically agitate the phosphor during removal of photoresist material, and it is an object of the present invention to fill that need.
According to one embodiment of the present invention, a method is provided for producing high resolution displays, the method comprising: depositing an electrically conductive coating over a screening surface; shielding the electrically conductive coating with a grille having a set of holes formed therein exposing a set of areas of the electrically conductive coating; applying a layer of insulative photoresist to the grille and the exposed areas of electrically conductive coating, whereby a plurality of photoresist-covered conductive areas are defined; fixing one set of the plurality of photoresist-covered conductive areas, whereby a fixed set is defined, and an unfixed set is defined; removing the photoresist from the unfixed set; depositing a light emitting substance on the exposed-conductive area; and plasma etching the fixed set of insulative photoresist.
According to a further embodiment of the invention, a system for producing high resolution displays is also provided. The system comprising: depositor of an electrically conductive coating over a screening surface; depositor of a grille having a set of holes formed therein applied to the screening surface and exposing a set of areas of the electrically conductive coating; applicator of a layer of insulative photoresist to the grille and the exposed areas of electrically conductive coating, whereby a plurality of photoresist-covered conductive areas are defined; fixer of one set of the plurality of photoresist-covered conductive areas, whereby a fixed set is defined, and an unfixed set is defined; remover of the photoresist from the unfixed set; depositor of a light emitting substance on the exposed-conductive area; and plasma etcher of the fixed set of insulative photoresist.